Структура и класс

#include <iostream>
#include <string>
 
using namespace std;
 
//Structure with books
struct Book
{
    string title;
    string author;
    string edition;
    int year;
public:
// Constructor of structure
    Book(string t = "", string a = "", string e = "", int y = 0)
    {
        title = t;
        author = a;
        edition = e;
        year = y;
    }
// Overloaded output operation 
    friend istream& operator>>(istream& is, Book& b)
    {
        is >> b.title >> b.author >> b.edition >> b.year;
        return is;
    }
};
 
//Library class
 
class Library 
{
    Book *b; //pointer 
    int count; //counter
public:
//Constructor of library
    Library(int n = 0)
    {
        b = new Book[count = n];
    }
//Book input
    void Add(Book x)
    {
        static int top = 0;
        b[top++] = x;
    }
//Searching by title
    void SearchTitle(char *title)
    {
        for (int i = 0; i < count; i++)
        {
            if (title == b[i].title)
            {
                cout << "Title: " << b[i].title << endl;
                cout << "Author: " << b[i].author << endl;
                cout << "Edition: " << b[i].edition << endl;
                cout << "Year: " << b[i].year << endl;
            }
            else
                cout << "Book you looking for does not exist" << endl;
        }
    }
//Searching by author
    void SearchAuthor(char *author)
    {
        for (int i = 0; i < count; i++)
        {
            if (author == b[i].author)
            {
                cout << "Title: " << b[i].title << endl;
                cout << "Author: " << b[i].author << endl;
                cout << "Edition: " << b[i].edition << endl;
                cout << "Year: " << b[i].year << endl;
            }
            else
                cout << "Book you looking for does not exist" << endl;
        }
    }
//Searching by year
    void SearchYear(int year)
    {
        for (int i = 0; i < count; i++)
        {
            if (year == b[i].year)
            {
                cout << "Title: " << b[i].title << endl;
                cout << "Author: " << b[i].author << endl;
                cout << "Edition: " << b[i].edition << endl;
                cout << "Year: " << b[i].year << endl;
            }
            else
                cout << "Book you looking for does not exist" << endl;
        }
    }
};
 
 
//Main function
void main()
{
    int n, year;
    char *title, *author, choice;
    cout << "Enter the number of books: ";
    cin >> n;
    Library lib(n);
 
    Book b;
    cout << "Enter title, author, edition and year of book in this order: " << endl;
    for (int i = 0; i < n; i++)
    {
        cin >> b;
        lib.Add(b);
    }
 
    cout << "Searching book: \n1-By title \n2-By author \n3-By year" << endl;
    cin >> choice;
    switch (choice)
    {
    case '1':
        cout << "Enter a title of the book: "; cin >> title;
        lib.SearchTitle(title);
        break;
    case '2':
        cout << "Enter an author of the book: "; cin >> author;
        lib.SearchAuthor(author);
        break;
    case '3':
        cout << "Enter a year of the book: "; cin >> year;
        lib.SearchYear(year);
        break;
    default:
        break;
    }
    system("pause");
}